Procalcitonina es superior a recuento linfocitario, índice neutrófilo/linfocito y proteína C reactiva para la predicción de mortalidad a 30 días de pacientes con COVID-19 en el servicio de urgencias / Procalcitonin concentration in the emergency department predicts 30-day mortality in COVID-19 better than the lymphocyte count, the neutrophil-to- lymphocyte ratio, or the C-reactive protein level

Introducción. Existen múltiples variables demográficas y clínicas predictivas de mortalidad en pacientes con COVID-19. Sin embargo, hay menos información sobre el valor pronóstico de los biomarcadores inflamatorios. Métodos. Estudio de cohorte retrospectivo. Se incluyeron de forma consecutiva todos los pacientes con COVID-19, confirmado por laboratorio, atendidos en un servicio de urgencias hospitalario (SUH) y con valor basal de los siguientes biomarcadores: recuento linfocitario, índice neutrófilo/linfocito (INL), proteína C reactiva (PCR) y procalcitonina (PCT). La relación entre los biomarcadores y la mortalidad total a 30 días se analizó mediante una regresión de Cox y gráficos de dosis-respuesta. Resultados. Se incluyeron 896 pacientes, 151 (17%) fallecieron en los primeros 30 días. La mediana de edad fue de 63 años (51-78) y 494 (55%) eran hombres. El valor de INL, PCR y PCT fue mayor, mientras que el recuento linfocitario fue menor, en los pacientes que fallecieron respecto a los que sobrevivieron (p < 0,001). La PCT fue superior al recuento linfocitario, INL y PCR en la predicción de mortalidad a 30 días (ABC 0,79 [IC 95%: 0,75-0,83] vs 0,70 [IC 95%: 0,65-0,74], p < 0,001; 0,74 [IC 95%: 0,69-0,78], p = 0,03; y 0,72 [IC 95%: 0,68-0,76], p < 0,001). Los puntos de decisión de PCT propuestos, 0,06 ng/l para exclusión y 0,72 ng/l para inclusión de muerte a 30 días, podrían facilitar la toma de decisiones en urgencias. Hubo 357 pacientes (40%) con valores de PCT en estas categorías. El análisis multivariable mostró una mayor asociación con la mortalidad para PCT que en los otros biomarcadores estudiados. Conclusión. PCT es el biomarcador con mejor capacidad para predecir mortalidad a 30 días por cualquier causa en pacientes con COVID-19 valorados en un SUH.

Background. Although many demographic and clinical predictors of mortality have been studied in relation to COVID-19, little has been reported about the prognostic utility of inflammatory biomarkers. Methods. Retrospective cohort study. All patients with laboratory-confirmed COVID-19 treated in a hospital emergency department were included consecutively if baseline measurements of the following biomarkers were on record: lymphocyte counts, neutrophil-to-lymphocyte ratio NRL, and C-reactive protein (CRP) and procalcitonin (PCT) levels. We analyzed associations between the biomarkers and all-cause 30-day mortality using Cox regression models and dose–response curves. Results. We included 896 patients, 151 (17%) of whom died within 30 days. The median (interquartile range) age was 63 (51-78) years, and 494 (55%) were men. NLR, CRP and PCT levels at ED presentation were higher, while lymphocyte counts were lower, in patients who died compared to those who survived (P < .001). The areas under the receiver operating characteristic curves revealed the PCT concentration (0.79; 95% CI, 0.75-0.83) to be a better predictor of 30-day mortality than the lymphocyte count (0.70; 95% CI, 0.65-0.74; P < .001), the NLR (0.74; 95% CI, 0.69-0.78; P = .03), or the CRP level (0.72; 95% CI, 0.68-0.76; P < .001). The proposed PCT concentration decision points for use in emergency department case management were 0.06 ng/L (negative) and 0.72 ng/L (positive). These cutoffs helped classify risk in 357 patients (40%). Multivariable analysis demonstrated that the PCT concentration had the strongest association with mortality. Conclusion. PCT concentration in the emergency department predicts all-cause 30-day mortality in patients with COVID-19 better than other inflammatory biomarkers.

Procalcitonin concentration in the emergency department predicts 30-day mortality in COVID-19 better than the lymphocyte count, the neutrophil-tolymphocyte ratio, or the C-reactive protein level. / Procalcitonina es superior a recuento linfocitario, índice neutrófilo/linfocito y proteína C reactiva para la predicción de mortalidad a 30 días de pacientes con COVID-19 en el servicio de urgencias.

OBJECTIVES: Although many demographic and clinical predictors of mortality have been studied in relation to COVID-19, little has been reported about the prognostic utility of inflammatory biomarkers. MATERIAL AND METHODS: Retrospective cohort study. All patients with laboratory-confirmed COVID-19 treated in a hospital emergency department were included consecutively if baseline measurements of the following biomarkers were on record: lymphocyte counts, neutrophil-to-lymphocyte ratio NRL, and C-reactive protein (CRP) and procalcitonin (PCT) levels. We analyzed associations between the biomarkers and all-cause 30-day mortality using Cox regression models and dose-response curves. RESULTS: We included 896 patients, 151 (17%) of whom died within 30 days. The median (interquartile range) age was 63 (51-78) years, and 494 (55%) were men. NLR, CRP and PCT levels at ED presentation were higher, while lymphocyte counts were lower, in patients who died compared to those who survived (P .001). The areas under the receiver operating characteristic curves revealed the PCT concentration (0.79; 95% CI, 0.75-0.83) to be a better predictor of 30-day mortality than the lymphocyte count (0.70; 95% CI, 0.65-0.74; P .001), the NLR (0.74; 95% CI, 0.69-0.78; P = .03), or the CRP level (0.72; 95% CI, 0.68-0.76; P .001). The proposed PCT concentration decision points for use in emergency department case management were 0.06 ng/L (negative) and 0.72 ng/L (positive). These cutoffs helped classify risk in 357 patients (40%). Multivariable analysis demonstrated that the PCT concentration had the strongest association with mortality. CONCLUSION: PCT concentration in the emergency department predicts all-cause 30-day mortality in patients with COVID-19 better than other inflammatory biomarkers.

OBJETIVO: Existen múltiples variables demográficas y clínicas predictivas de mortalidad en pacientes con COVID-19. Sin embargo, hay menos información sobre el valor pronóstico de los biomarcadores inflamatorios. METODO: Estudio de cohorte retrospectivo. Se incluyeron de forma consecutiva todos los pacientes con COVID-19, confirmado por laboratorio, atendidos en un servicio de urgencias hospitalario (SUH) y con valor basal de los siguientes biomarcadores: recuento linfocitario, índice neutrófilo/linfocito (INL), proteína C reactiva (PCR) y procalcitonina (PCT). La relación entre los biomarcadores y la mortalidad total a 30 días se analizó mediante una regresión de Cox y gráficos de dosis-respuesta. RESULTADOS: Se incluyeron 896 pacientes, 151 (17%) fallecieron en los primeros 30 días. La mediana de edad fue de 63 años (51-78) y 494 (55%) eran hombres. El valor de INL, PCR y PCT fue mayor, mientras que el recuento linfocitario fue menor, en los pacientes que fallecieron respecto a los que sobrevivieron (p 0,001). La PCT fue superior al recuento linfocitario, INL y PCR en la predicción de mortalidad a 30 días (ABC 0,79 [IC 95%: 0,75-0,83] vs 0,70 [IC 95%: 0,65-0,74], p 0,001; 0,74 [IC 95%: 0,69-0,78], p = 0,03; y 0,72 [IC 95%: 0,68-0,76], p 0,001). Los puntos de decisión de PCT propuestos, 0,06 ng/l para exclusión y 0,72 ng/l para inclusión de muerte a 30 días, podrían facilitar la toma de decisiones en urgencias. Hubo 357 pacientes (40%) con valores de PCT en estas categorías. El análisis multivariable mostró una mayor asociación con la mortalidad para PCT que en los otros biomarcadores estudiados. CONCLUSIONES: PCT es el biomarcador con mejor capacidad para predecir mortalidad a 30 días por cualquier causa en pacientes con COVID-19 valorados en un SUH.

An opportunity to emphasize the relevance of laboratory medicine.

Objectives: Clinical practice guidelines (CPGs) are recommendations based on a systematic review of scientific evidence that are intended to help healthcare professionals and patients make the best clinical decisions. CPGs must be evidence-based and are designed by multidisciplinary teams. The purpose of this study is to assess the topics related to the clinical laboratory addressed in CPGs and evaluate the involvement of laboratory professionals in the CPG development process. Methods: A total of 16 CPGs recommended by the Spanish Society of Laboratory Medicine and/or retrieved from PubMed-Medline were included. A review of the information provided in CPGs about 80 topics related to the clinical laboratory was performed. The authorship of laboratory professionals was assessed. Results: On average, the 16 CPGs addressed 49% (standard deviation [SD]: 11%) of the topics evaluated in relation to the clinical laboratory. By order of frequency, CPGs contained information about 69% of postanalytical variables (SD: 20%); 52% of preanalytical variables (SD: 11%); and 43% of the analytical variables studied (SD: 18%). Finally, half the CPGs included a laboratory professional among its authors. Conclusions: CPGs frequently failed to provide relevant laboratory-related information. Laboratory professionals were co-authors in only half the CPGs. There is scope for improvement, and laboratory professionals should be included in multidisciplinary teams involved in the development of CPGs.

Recursos y fuentes de infomación útiles en la práctica de la medicina de laboratorio basado en la evidencia / Resources and sources useful in evidence-based laboratory medicine practice

No disponible

Development and validation of an HPLC-MS method for a simultaneous measurement of oxalate and citrate in urine / Desarrollo y validación de un método de HPLC-MS para la medida simultánea de oxalato y citrato en orina

Objectives. An increased urinary oxalate and reduced urinary citrate are considered major risk factors in the formation of calcium oxalate kidney stones. In this work, an HPLC-MS method is presented for the simultaneous measurement of oxalate and citrate in urine. Methods. Sample preparation was carried out using a liquid-liquid extraction with ethyl acetate. Chromatographic separation was performed in a C18 column by gradient elution with methanol and 1 M formate buffer at 35 °C. Citrate and oxalate were monitored on a single-quadrupole MS system. Results. The method was linear in the concentration range of 0.5 mg/L to 450 mg/L for oxalate and from 2.5 mg/L to 950 mg/L for citrate. The Lower Limit of Measurement was 0.56 mg/L for oxalate and 2.5 mg/L for citrate. The within-day imprecision was 6% for oxalate and 3% for citrate, and the between day imprecision was lower than 15% for both analytes. LC-MS method was compared with capillary electrophoresis and it was shown that both methods were interchangeable to measure oxalate, but not citrate. Conclusions. HPLC-MS method is a good approach to measure oxalate and citrate in 24-hour urine, and it is applicable in clinical routine for patients with recurrent stone formation (AU)

Objetivos. La hiperoxaluria e hipocitraturia están consideradas el principal factor de riesgo en la formación de cálculos renales de oxalato cálcico. En este trabajo se ha desarrollado un método de HPLC-MS para la medida simultánea de oxalato y citrato en orina. Métodos. La preparación de muestras se realizó por una extracción líquido-líquido con etilacetato. La separación cromatográfica se llevó a cabo en una columna C-18 a 35 °C con un gradiente de elución con metanol y ácido fórmico 1 M. El citrato y el oxalato se monitorizaron mediante espectrometría de masas con un cuadrupolo simple. Resultados. El método fue lineal para el oxalato en el rango de concentración de 0,5 a 450 mg/l y para el citrato de 2,5 a 950 mg/l. El límite menor de intervalo de medida fue de 0,56 mg/l para el oxalato y de 2,5 mg/l para el citrato. La imprecisión intradía fue del 6% para el oxalato y del 3% para el citrato, y la interdía fue inferior al 15% para ambos analitos. El método de LC-MS desarrollado se comparó con un método de electroforesis capilar y se demostró que ambos eran intercambiables para el oxalato, pero no para el citrato. Conclusiones. El método de HPLC-MS desarrollado constituye una buena aproximación para medir oxalato y citrato en orina de 24 horas y es aplicable en la rutina clínica para pacientes con riesgo de formación de cálculos renales (AU)

Development of a method for the quantitative analysis of urinary stones, formed by a mixture of two components, using infrared spectroscopy.

OBJECTIVES: The analysis of urinary stones is used for the diagnosis of the etiology of an episode of nephrolithiasis. The technique considered as standard for this purpose is infrared spectroscopy (IR). However, when the urinary stone is formed by a mixture of components, only semi-quantitative information can be achieved using IR. The objective of this work is the development of a quantitative method. DESIGN AND METHODS: Bands in the IR spectra of several mixtures were studied, in order to design a calibration model useful to determine the quantitative composition of the urinary stones. For mixtures of two components, four mathematical models were proposed. To assess the validity of these models, nine series of mixtures of two components were prepared, using the most frequently compounds found in urinary stones, for analyzing by ATR-FTIR spectroscopy (Attenuated Total Reflection Fourier Transformed Infrared). RESULTS: Nine series of nine mixtures of two components were prepared for this work. The IR spectrum was recorded for each mixture and the absorbance intensities at selected wave numbers were used to apply the proposed mathematical models. There were good linear correlations between the analytical signals (IR absorbances) and the analytical responses (weight fractions) using the calibration lines. The validity of the method was checked by the comparison between the weight fractions resulted from the calibration lines and the real weight fractions obtained by weighing, presenting good correlation parameters. CONCLUSIONS: The method developed in this work has been useful for the quantification of compounds which are commonly found in urinary stones. This method allows a total characterization of the urinary stones (qualitative and quantitative) by means of IR spectroscopy.